Present day electronic energy meters and registers have greatly expanded capabilities and are being called upon to provide additional functions beyond simple indications of kilowatt hour consumption and kilowatt demand. Examples of such additional functions are pulse initiators, time of use rate period indications, end of demand interval indicator, load control signals, a demand threshold indicator, and an external control signal to inhibit accumulation of pulses in various register modes. In addition, the relative complexity of such electronic meters, which include microprocessors and data processing circuitry, requires the use of sophisticated electronic test equipment in the repair of such meters. It has become necessary to provide external signals to an electronic energy meter, and to bring electronic signals out of the electronic energy meter. However, many of the connections, configurations, and dimensions of an energy meter are defined by industry standards, namely the American National Standards Institute (ANSI) standards. For example, some transformer rated versions of the ANSI standard S-base meter have provisions for the pulse initiator KYZ output connections to be made through spare terminals in the meter. Various approaches have been suggested or utilized to provide additional means for bringing signals into or out of electronic energy meters. One method has been to provide a short multi-conductor cable protruding through a hole in the base of the meter and terminating in a connector which then can be connected to external equipment. However, not every energy meter requires external signals such that it is desirable to have a standard energy meter which is flexible in enabling external signals to be provided by the manufacturer at the time of manufacture, or to be added later by the end user or by the manufacturer. That is, it is highly desirable to have the flexibility built into a standard energy meter for later customizing as required, including the ability to provide or connect to external signals.
In addition, electronic energy meters are constructed in a layered configuration with the socket or base forming the bottom layer, and the register or meter which provides the readings at the top layer. Also, there may be one or more intermediate layers of electronics, such as electronic circuit boards, provided. It is important that the construction of such layered meters be provided with proper structural support and integrity. While external signals may be connected to a plurality of layers in the energy meter, it is highly desirable that the external connector be provided through the base of the meter.
In addition, the control signals in an electronic energy meter are often not suitable for direct use outside the meter, and electronic signal conditioning is generally required. In those meters where external signals are required, it is desirable that the signal conditioning circuitry be added to the interior of the energy meter. It is also desirable to provide for the additional signal conditioning circuitry to be selectively added by the manufacturer during or after manufacture, or by the end user after delivery, and even use of, the energy meter. The cost of manufacturing electronic energy meters and the delivery cycle can be reduced if a standard, but flexible meter can be manufactured and stocked with the various customer requirements and features later, and selectively added; that is, providing the ability to accommodate the late point identification of features.